WO2013078993A1

WO2013078993A1 - Method for manufacturing microwave dielectric ceramic material

Info

Publication number: WO2013078993A1
Application number: PCT/CN2012/085435
Authority: WO
Inventors: 赵可沦; 申风平; 陈鲁国
Original assignee: 深圳市大富科技股份有限公司
Priority date: 2011-11-30
Filing date: 2012-11-28
Publication date: 2013-06-06

Abstract

A method for manufacturing a microwave dielectric ceramic material, comprising: mixing mechanically and uniformly a powder mixture of a carbonate, aluminum oxide, lanthanum oxide, and titanium dioxide, forming powder particles; high-energy ball milling for the first time the powder particles to refine uniformly the powder particles; high-temperature sintering in a sealed container the powder that was high-energy ball milled for the first time, forming a precursor powder; and high-energy ball milling for the second time the precursor powder to further refine uniformly the precursor powder, forming a ceramic powder. The present invention allows for lowered sintering temperature, for reduced sintering time, for reduced production costs and technical difficulty, and for high densification.

Description

Method for preparing microwave dielectric ceramic material

[Technical Field]

The invention relates to the technical field of ceramic materials, in particular to a method for preparing a microwave dielectric ceramic material.

【Background technique】

Microwave dielectric ceramics are novel functional electronic ceramic materials with excellent dielectric properties in the microwave frequency range of 300MHz~300GHz. They function as dielectric isolation, dielectric waveguide and dielectric resonance in microwave circuits.

Since the perovskite structure (Ca,Sr)Ti0 ₃ —LaA10 ₃ (x represents a mole percent)-based microwave dielectric ceramic material has a higher dielectric constant (30< ε r<45), a temperature coefficient of resonance frequency close to zero ( τ f~0) and a fairly high quality factor (QX 30000) have caused widespread concern and research in the industry. However, for the less expensive CaTi0 ₃ -LaA10 ₃ -based microwave dielectric ceramic material or SrTi0 ₃ -LaA10 ₃ -based microwave dielectric ceramic material, the industry's research mainly depends on the relationship between its microstructure and dielectric properties. There are few studies on preparation methods.

At present, most domestic and foreign manufacturers adopt a combination of mechanical mixing and solid-phase sintering. The solid powder raw materials are thoroughly mixed in a planetary or agitated ball mill and then solid-phase reaction is carried out under high-temperature calcination conditions to prepare the desired The ceramic powder is pressed and formed into a dielectric ceramic material. This conventional preparation method mainly has the following defects: The powder has poor reactivity during high-temperature sintering and requires a high sintering temperature (CaTi0 ₃ -LaA10 ₃ -based microwave dielectric ceramic material is 1500~1650 degrees Celsius, SrTi0 ₃ -LaA10 ₃ The microwave-based dielectric ceramic material is in the range of 1580~1680 degrees Celsius and 4艮 long sintering time (CaTi0 ₃ - LaA10 ₃ microwave dielectric ceramic material in 12~24 hours), resulting in extremely high production energy consumption, even if liquid phase sintering is used. To reduce the sintering temperature, the degree of reduction is also limited (CaTi0 _{3 -} LaA10 ₃ based microwave dielectric ceramic material down to 1450 degrees Celsius, SrTi0 _{3 -} LaA10 ₃ based microwave dielectric ceramic material reduced 1430~1460 degrees Celsius), it will also damage the dielectric properties of the finished product to varying degrees; The synthetic ceramic powder has a large particle size and a wide particle size distribution, which is difficult to achieve high density of sintering, and its hooking property is only extended by mixing. Time to ensure that it is difficult to obtain a dielectric ceramic material with stable and excellent microwave dielectric properties; for CaTi0 ₃ -LaA10 ₃ microwave dielectric ceramic material, it ignores the "defective effect" caused by the volatile element Ca in the sintering process. Adverse effects due to performance.

[Summary of the Invention]

The technical problem to be solved by the present invention is to provide a method for preparing a microwave dielectric ceramic material, which can reduce the sintering temperature and shorten the sintering time in the process of preparing the microwave dielectric ceramic material.

In order to solve the above technical problem, a technical solution adopted by the present invention is: Providing a method for preparing a microwave dielectric ceramic material, comprising: mechanically mixing a mixed powder of a carbonate, an alumina, a cerium oxide and a titanium dioxide; Forming powder particles, wherein the carbonate is 4丐 carbonate or barium carbonate; the powder particles are subjected to a first high-energy ball milling to knead the powder particles; the first high-energy ball milled powder is The high temperature calcination in the closed vessel forms a precursor powder; the precursor powder is subjected to a second high energy ball milling to further uniformly refine the precursor powder to form a ceramic powder.

Wherein, after the second high-energy ball milling step, the method further comprises: spray granulation, adding a polyvinyl alcohol aqueous solution having a concentration of 5% and a mass percentage of 5% to 10% to the ceramic powder, and forming the ceramic powder into a spherical flow. Sexual powder particles.

Wherein, after the spray granulation step, the method further comprises: press forming, and the powder particles having spherical fluidity are formed into a compact of a desired shape.

The press forming step further comprises: sintering, continuously sintering the compact to form a ceramic blank, wherein the maximum sintering temperature is 1300-1500 degrees Celsius, and the holding time is 3-6 hours.

Among them, in the high-temperature calcination step, the closed container is resistant to high temperature, the calcination temperature is 1100 to 1350 degrees Celsius, and the holding time is 3 to 5 hours.

Wherein, the precursor powder is subjected to a second high-energy ball milling step, and a modified dopant, a modifying additive and a sintering aid are further added. Wherein, the modified dopant is an oxide containing a rare earth element, and the rare earth element is one or more of lanthanum, cerium, lanthanum, cerium, lanthanum, cerium, cerium, lanthanum, cerium, and town. The additive is one or more of CaO, SrO, Ti0 ₂ , ZnO, A1 ₂ 0 ₃ , Nb ₂ 0 ₅ and Ta ₂ 0 ₅ , and the sintering aid is Bi ₂ 0 ₃ , B ₂ 0 ₃ , One or more of CuO, V ₂ 0 ₅ and BaO.

Among them, the carbonate is barium carbonate.

Wherein, the molar percentage of alumina and cerium oxide in the powder is 0.15 mol% to 0.45 mol%, the molar percentage of the cerium carbonate and titanium oxide is 0.1 mol% to 0.7 mol%, and the purity of cerium carbonate and aluminum oxide are both greater than 99.5. %, the purity of titanium dioxide and cerium oxide is not less than 99.9%.

Wherein, the step of mechanically uniformly mixing the mixed powder of lanthanum carbonate, aluminum oxide, cerium oxide and titanium dioxide comprises: adding a zirconia grinding ball as a grinding medium in a spherical tank, adding anhydrous ethanol or deionized water as an organic solvent. The mixed powder is mechanically mixed, and after the powder particles are formed, the organic solvent is removed and dried, wherein the mixed powder, the grinding medium and the organic solvent are in a weight ratio of 1:3:3 and occupy the spherical tank. The volume is 60%~80%, and the mixing time is 6~10 hours.

Among them, the powder particles are subjected to the first high-energy ball milling step, the ball-to-batch ratio is 8:1~10:1, the ball milling time is 3-6 hours, and the rotation speed is 400-800 rpm.

Among them, the precursor powder is subjected to the second high-energy ball milling step, the ball-to-batch ratio is 10:1~12:1, the ball milling time is 3-6 hours, and the rotation speed is 600~1000 rpm.

Among them, the ceramic powder after the second high-energy ball milling has a particle size of less than 1 μ ηι.

Wherein, the formula of the microwave dielectric ceramic material is such that the molar percentages X and y thereof satisfy 0.3 mol% < x < 0.9 mol%, respectively, according to the chemical formula (1-χ)8ι·Ή0 ₃ -χ[Ι^ _1-γ Κ Α10 ₃ ] , 0.1 mol% < y < 0.5 mol%, wherein the mass percentage of the modifying additive is 1% to 4% of the total amount of cerium carbonate, aluminum oxide, cerium oxide and titanium dioxide, and the mass percentage of the sintering aid is cerium carbonate, oxidation 0.1% to 1% of the total amount of aluminum, cerium oxide and titanium dioxide.

Among them, the carbonate is 4丐 carbonate.

Wherein, the microwave dielectric ceramic material is formulated according to the chemical formula (lx) Ca ₁₊ yTi0 ₃ —x[La _1-z Re _z A10 ₃ ] such that the molar percentages x, y and z thereof respectively satisfy 0.1 mol% < x < 0.7 mol % , 0.1mol% < y < 0.5 mol% and 0.01 mol% < z < 0.1 mol%, the purity of calcium carbonate and alumina are both greater than 99.5%, and the purity of titanium dioxide and cerium oxide is not less than 99.9%.

Wherein, the step of mechanically uniformly mixing the mixed powder of carbonic acid, aluminum oxide, cerium oxide and titanium dioxide comprises: adding a zirconia grinding ball as a grinding medium in a spherical tank, adding anhydrous ethanol or deionized water as an organic solvent The solvent mixes the mixed powders mechanically, and after forming the powder particles, the organic solvent is removed and dried, wherein the mixed powder, the grinding medium and the organic solvent are in a weight ratio of 1:3:3 and occupy the ball. The tank volume is 60%~80%, and the mixing time is 1~3 hours.

Among them, the powder particles are subjected to the first high-energy ball milling step, the ball-to-batch ratio is 8:1~10:1, the ball milling time is 1-3 hours, and the rotation speed is 600-800 rpm.

Among them, the precursor powder is subjected to the second high-energy ball milling step, the ball-to-batch ratio is 10:1~12:1, the ball milling time is 1-3 hours, and the rotation speed is 800-1000 rpm.

Wherein, the microwave dielectric ceramic material is formulated according to the chemical formula (lx) Ca ₁₊ yTi0 ₃ —x[La _1-z Re _z A10 ₃ ] such that the molar percentages x, y and z thereof respectively satisfy 0.1 mol% < x < 0.7 mol %, 0.1 mol% < y < 0.5 mol% and 0.01 mol% < z < 0.1 mol%, wherein the mass percentage of the modifying additive is 1% to 4% of the total amount of calcium carbonate, aluminum oxide, cerium oxide and titanium oxide %, the mass percentage of the sintering aid is 0.1% to 1% of the total amount of calcium carbonate, aluminum oxide, cerium oxide and titanium dioxide.

In summary, the preparation method of the microwave dielectric ceramic material of the present invention can reduce the sintering temperature and the sintering time to a large extent by performing high-energy ball milling in the manufacturing process, and achieve high densification, thereby reducing the Production costs and technical difficulties.

The above description is only an overview of the technical solutions of the present invention, and the technical means of the present invention can be more clearly understood, and the above and other objects, features and advantages of the present invention can be more clearly understood. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments will be described in detail with reference to the accompanying drawings.

[Description of the Drawings]

1 is a schematic flow chart of a method for preparing a microwave dielectric ceramic material according to an embodiment of the present invention; 2 is a particle size distribution diagram of a powder prepared by conventional mechanical mixing (a) and first high energy ball milling (b), respectively, in a method of preparing a microwave dielectric ceramic material according to an embodiment of the present invention;

3 is a schematic diagram of a method for preparing a microwave dielectric ceramic material according to an embodiment of the present invention, wherein a conventional mechanical mixing + solid phase reaction method (a) and a mechanical mixing of the present invention combined with a high energy ball milling method (b) are used to prepare an STLA-based microwave medium. Scanning electron microscopy (SEM) image of ceramic samples;

4 is a particle size distribution of a powder prepared by conventional mechanical mixing (12 hours) (a) and first high energy ball milling (2 hours) (b), respectively, in a method of preparing a microwave dielectric ceramic material according to an embodiment of the present invention. Figure

5 is a schematic diagram of a method for preparing a microwave dielectric ceramic material according to an embodiment of the present invention, wherein a conventional mechanical mixing + solid phase reaction method (a) and a mechanical mixing combined with high energy ball milling method (b) of the present invention respectively produce CTLA-based microwaves. Scanning electron microscopy (SEM) images of dielectric ceramic samples.

DETAILED DESCRIPTION

BRIEF DESCRIPTION OF THE DRAWINGS The technical solutions in the embodiments of the present invention will be described in detail with reference to the accompanying drawings. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without making creative labor are within the scope of the present invention.

Embodiment 1

A method for preparing a microwave dielectric ceramic material, the flow diagram of which is shown in FIG. 1 , comprising: step S101, mechanically uniformly mixing a mixed powder of carbonate, alumina, cerium oxide and titanium dioxide to form powder particles, Among them, the carbonate is calcium carbonate or barium carbonate.

In this embodiment, the carbonate is cesium carbonate. The mixed powder of barium carbonate, alumina, cerium oxide and titanium dioxide is weighed according to the required molar percentage formula, placed in a spherical tank for mechanical uniform mixing, and added with zirconia grinding balls as grinding media, added with absolute ethanol or Deionized water is used as an organic solvent, and after the powder particles are formed, the organic solvent is removed for drying, the mixed powder, the grinding medium, and The weight ratio of the three solvents is 1:3:3 and accounts for 60%~80% of the volume of the spherical tank, and the mixing time is 6-10 hours. Wherein, the molar percentage of cerium carbonate and titanium dioxide is 0.1 mol% to 0.7 mol%, and the molar percentage of alumina and cerium oxide is 0.15 mol% to 0.45 mol%. The purity of barium carbonate and aluminum oxide is more than 99.5%, and the purity of titanium dioxide and barium oxide is not less than 99.9%.

In other embodiments, the carbonate is calcium carbonate. Further adding a zirconia grinding ball as a grinding medium in the spherical tank and adding anhydrous ethanol or deionized water as an organic solvent to mechanically uniformly mix the mixed powder, and after forming the powder particles, removing the organic solvent for drying, The mixing ratio of the mixed powder, the grinding medium and the organic solvent is 1:3:3 and accounts for 60%~80% of the volume of the spherical tank, and the mixing time is 1~3 hours. Imol% < x < 0.7, the composition of the microwave dielectric ceramic material according to the formula (lx) Ca ₁₊ yTi0 ₃ - x [La _1-z Re _z A10 ₃ ] wherein the molar percentages x, y and z respectively satisfy 0. lmol% < x < 0.7 Mol%, 0.1 mol% < y < 0.5 mol% and 0.01 mol% < z < 0.1 mol%, the purity of calcium carbonate and alumina are both greater than 99.5%, and the purity of titanium dioxide and cerium oxide is not less than 99.9%. By increasing the mole percentage of carbonic acid 4, the "defective effect" caused by the volatile element Ca can be suppressed.

Step S102, the powder particles are subjected to a first high-energy ball milling to uniformly refine the powder particles. In this embodiment, the first high-energy ball milling is performed using the zirconia grinding ball as a grinding medium for high-energy ball milling, and the particle size distribution of the powder after the first high-energy ball milling is in the range of 1~2 μ ηι, effectively improving The reactivity and contact area of the powder particles are further reduced, thereby achieving the purpose of lowering the synthesis temperature of the calcination reaction. When the carbonate is barium carbonate, the ball to material ratio is 8:1 to 10:1, and the ball milling time is 3-6. Hour, the speed is 400-800 rev / min; when the carbonate is 4 碳酸 carbonate, the ball-to-batch ratio is 8: 1~10: 1 , the ball milling time is 1~3 hours, and the rotation speed is 600~800 rpm.

Step S103, the first high-energy ball-milled powder is calcined at a high temperature in a closed vessel to form a precursor powder.

In the present embodiment, the first high-energy ball-milled powder is placed in a sealed high-temperature resistant crucible, and a high-purity main crystalline phase precursor powder is synthesized by a high temperature reaction. The process parameters of the high-temperature calcination process are as follows: The closed vessel is resistant to high temperature, the calcination temperature is 1100~1350 degrees Celsius, and the holding time is 3~5 hours.

Step S104, performing a second high-energy ball milling on the precursor powder to further advance the precursor powder It is evenly refined to form a ceramic powder.

In this embodiment, the zirconia grinding ball is used as a grinding medium for high energy ball milling, and a modified dopant, a modification additive and a sintering aid are further added for the second high energy ball milling. The ceramic powder formed by the control has a particle size smaller than Ι μ ηι, the modified dopant is an oxide containing a rare earth element, and the rare earth elements are lanthanum, cerium, lanthanum, cerium, lanthanum, cerium, 4L, lanthanum, cerium, and lanthanum. One or more, the modifying additive is one or more of CaO, SrO, Ti0 ₂ , ZnO, A1 ₂ 0 ₃ , Nb ₂ 0 ₅ and Ta ₂ 0 ₅ , and the sintering aid is Bi ₂ 0 ₃ , One or more of B ₂ 0 ₃ , CuO, V ₂ 0 ₅ and BaO.

When the carbonate is barium carbonate, the microwave dielectric ceramic material is formulated according to the formula (lx)SrTi0 ₃ — χ[Ι^ _1-γ Κ Α 10 ₃ ] such that the molar percentages x and y thereof respectively satisfy 0.3 mol% < x < 0.9 mol%, 0.1 mol% < y < 0.5 mol%, wherein the mass percentage of the modifying additive is 1% to 4% of the total amount of cerium carbonate, aluminum oxide, cerium oxide and titanium oxide, and the mass percentage of the sintering aid is carbonic acid 0.1% to 1% of the total amount of cerium, aluminum oxide, cerium oxide and titanium dioxide. By adding a modified dopant, a modification additive and a sintering aid, the purpose of lowering the sintering temperature and densification of the microwave dielectric ceramic can be achieved. Among them, the ball-to-batch ratio is 10: 1~12: 1 , the ball milling time is 3~6 hours, and the rotation speed is 600~1000 rev/min. When the carbonate is 4 碳酸 carbonate, the formulation of the microwave dielectric ceramic material is in accordance with the chemical formula (lx) Ca ₁₊ yTi0 ₃ —x[La _1-z Re _z A10 ₃ ], wherein the molar percentages _x , y and z thereof are respectively Satisfying 0. lmol% < x < 0.7 mol%, 0.1 mol% < y < 0.5 mol% and 0.01 mol% < z < 0.1 mol%, wherein the mass percentage of the modifying additive is calcium carbonate, aluminum oxide, cerium oxide and The total amount of titanium dioxide is 1% to 4%, and the mass percentage of sintering aid is 0.1% to 1% of the total amount of carbonic acid 4, alumina, cerium oxide and titanium dioxide. By adding a modified dopant, a modification additive and a sintering aid, the purpose of lowering the sintering temperature and densification of the microwave dielectric ceramic can be achieved. Among them, the ball-to-batch ratio is 10: 1~12: 1 , the ball milling time is 1~3 hours, and the rotation speed is 800~1000 rev/min.

Further, in the present embodiment, after the ceramic powder is formed, the following steps may be further included as needed:

Spray granulation, a polyvinyl alcohol aqueous solution having a concentration of 5% and a mass percentage of 5% to 10% is added to the ceramic powder, and the ceramic powder is made into powder particles having spherical fluidity, and the powder particles are fluid. it is good.

Press forming, the spherical particles having spherical fluidity are formed into a compact of a desired shape. In the present embodiment, the green compact is subjected to double-side press molding by a press in a manual or automatic filling manner, or one injection molding is performed by one injection molding technique.

Sintering, continuous sintering of the green compact to form a ceramic blank, wherein the highest sintering temperature is

1300~1500 degrees Celsius, holding time is 3~6 hours.

In the present embodiment, the green compact is placed in a closed high-temperature resistant alumina crucible for continuous sintering, and a solid phase reaction occurs at a high temperature to form a dense ceramic blank.

Machining and sample testing, the ceramic blank is surface treated to obtain a sample, and the dielectric properties of the sample are measured.

In this embodiment, the surface treatment can be performed by grinding, polishing, etc., to obtain a test sample of a desired size, and the dielectric performance index is measured by a network analyzer: dielectric constant ^ resonance frequency temperature coefficient T _f and quality Factor Q.

Embodiment 2

A method for preparing a microwave dielectric ceramic material, wherein the carbonate is barium carbonate, and the method of the generation comprises:

Step 1. Pre-sintering the cerium oxide raw powder at 800 ° C for 2 hours before batching, and pre-sintering the original titanium dioxide powder at 1280 ° C for 3 hours to dry; strontium carbonate according to the chemical formula 0.68 SrTiO ₃ — 0.32 LaAlO ₃ The alumina, cerium oxide and titanium dioxide mixed powder are placed in a spherical tank for mechanical hooking; the zirconia grinding ball is added as a grinding medium, anhydrous ethanol or deionized water is added as an organic solvent, and powder particles are formed. Thereafter, the organic solvent is removed for drying, and the ratio of the mixed powder, the grinding ball, and the solvent (weight) is 1:3:3 and it accounts for 80% of the volume of the spherical tank, and the mixing time of the raw material is 10 hours.

In the present embodiment, the stoichiometric ratio of cerium carbonate and titanium oxide was 0.72 mol%, and the stoichiometric ratio of alumina and cerium oxide was 0.28 mol%. It should be noted that the purity of the strontium carbonate and alumina powders is more than 99.5%, and the purity of the titanium dioxide and cerium oxide powders is not less than 99.9%.

Step 2: using the zirconia grinding ball as a grinding medium, drying the powder of the first step, and performing the first high-energy ball milling to obtain a uniformly refined mixed raw material. Among them, the high energy ball milling time is 6 hours, the ball to material ratio is 10: 1 , the speed is 500 rpm.

Step 3: The mixed raw material of the second step is placed in a sealed high temperature resistant crucible, and a precursor powder having a high purity main crystalline phase is synthesized by a high temperature calcination reaction; the calcination temperature is 1150 degrees Celsius, and the holding time is 5 hours.

Step 4: using a zirconia grinding ball as a grinding medium, and subjecting the calcined powder to a second high-energy ball milling to obtain a ceramic powder which is further uniformly refined. Among them, the high-energy ball milling time is 4 hours, the ball-to-batch ratio is 10:1, and the rotation speed is 1000 rpm.

Step 5: In step 4, a 10% by mass aqueous solution of polyvinyl alcohol (PVA) (concentration: 5%) is added to the powder, and a spherical and fluid powder particle is prepared by using a drying tower or a granulator.

Step 6. Using a press (manual or automatic packing) to form the powder particles into a compact of the desired shape, using double-sided pressing, the pressing pressure is 120 MPa; or, using a single injection molding technique, the desired shape can also be obtained. Compacted blank.

Step 7. Place the green compact into a sealed high temperature resistant alumina crucible for continuous sintering. Among them, the maximum sintering temperature is 1500 degrees Celsius, and the holding time is 6 hours.

Step 8. Take out the fired ceramic blank and obtain the desired test sample size by surface treatment such as grinding and polishing. Then, the dielectric properties of the network analyzer were measured as: £ _r = 56.4; Ti = 32.7 ppm / ° C; Q χ f = 46800 (test frequency is 10 GHz).

Embodiment 3

A method for preparing a microwave dielectric ceramic material, wherein the carbonate is barium carbonate, the preparation method comprises:

Step 1. Pre-sintering the cerium oxide powder at 800 °C for 2 hours before batching, and pre-sintering the titanium dioxide raw powder at 1280 ° C for 3 hours to dry; strontium carbonate according to the chemical formula 0.52SrTiO ₃ — 0.48 LaAlO ₃ The alumina, cerium oxide and titanium dioxide mixed powder are placed in a spherical tank for mechanical hooking; the zirconia grinding ball is added as a grinding medium, and anhydrous ethanol or deionized water is added as an organic solvent, and the powder and the grinding ball are mixed. The solvent (weight) ratio is 1:3:3 and it accounts for 60% of the volume of the spherical tank, and the raw material mixing time is 8 hours. In the present embodiment, the stoichiometric ratio of cerium carbonate and titanium oxide was 0.62 mol%, and the stoichiometric ratio of alumina and cerium oxide was 0.38 mol%. It should be noted that the purity of the cerium carbonate and the alumina powder is more than 99.5%, and the purity of the titanium dioxide and cerium oxide powder is not less than 99.9%.

Step 2: using the zirconia grinding ball as a grinding medium, the first dry powder is subjected to the first high-energy ball milling to obtain a uniformly refined mixed raw material. Among them, the high-energy ball milling time is 4 hours, the ball-to-batch ratio is 12:1, and the rotation speed is 800 rpm.

Step 3: The mixed raw material of the second step is placed in a closed high temperature resistant crucible, and a precursor powder having a high purity main crystalline phase is synthesized by a high temperature reaction. Among them, the calcination temperature was 1280 ° C and the holding time was 4 hours.

Step 4: using a zirconia grinding ball as a grinding medium, and subjecting the calcined powder to a second high-energy ball milling to obtain a ceramic powder which is further uniformly refined. Among them, the high-energy ball milling time is 4 hours, the ball-to-batch ratio is 10:1, and the rotation speed is 800 rpm.

Step 5: adding a mass percentage of 8% polyvinyl alcohol (PVA) aqueous solution (concentration: 5%) to the powder obtained in the fourth step, and using a drying tower or a granulator to form spherical and fluid powder particles. .

Step 7. Place the green compact into a sealed high temperature resistant alumina crucible for continuous sintering. Among them, the highest sintering temperature is 1450 degrees Celsius, and the holding time is 4 hours.

Step 8. Take out the fired ceramic blank and obtain the desired test sample size by surface treatment such as grinding and polishing. Then, the dielectric performance indicators measured by network analyzer are: s _r =45.3;

; Q χ f=63400 (test frequency is 10GHz).

Embodiment 4

Step 1. Pre-sinter the cerium oxide powder at 800 °C for 2 hours before compounding, and oxidize The titanium raw powder is pre-fired at 1280 ° C for 3 hours for drying; the mixed powder of lanthanum carbonate, aluminum oxide, cerium oxide and titanium dioxide is placed in a spherical tank according to the chemical formula 0.36SrTiO ₃ — 0.64 LaAlO ₃ for mechanically mixing; Adding zirconia grinding balls as grinding media, adding anhydrous ethanol or deionized water as organic solvent, the ratio of mixed powder, grinding balls and solvent (weight) is 1:3:3 and it accounts for 70% of the volume of the spherical tank. The mixing time of the raw materials was 8 hours.

In the present embodiment, the stoichiometric ratio of cerium carbonate and titanium oxide was 0.52 mol%, and the stoichiometric ratio of alumina and cerium oxide was 0.48 mol%. It should be noted that the purity of the strontium carbonate and alumina powders is more than 99.5%, and the purity of the titanium dioxide and cerium oxide powders is not less than 99.9%.

Step 2: using the zirconia grinding ball as a grinding medium, the first dry powder is subjected to the first high-energy ball milling to obtain a uniformly refined mixed raw material. Among them, the high-energy ball milling time is 5 hours, the ball-to-batch ratio is 10:1, and the rotation speed is 600 rpm.

Step 3: The mixed raw material of the second step is placed in a closed high temperature resistant crucible, and a precursor powder having a high purity main crystalline phase is synthesized by a high temperature reaction. Among them, the calcination temperature was 1250 degrees Celsius and the holding time was 6 hours.

Step 4: using a zirconia grinding ball as a grinding medium, and subjecting the calcined powder to a second high-energy ball milling to obtain a ceramic powder which is further uniformly refined. Among them, the high-energy ball milling time is 3 hours, the ball-to-batch ratio is 8:1, and the rotation speed is 1000 rpm.

Step 5: adding a mass percentage of 5% polyvinyl alcohol (PVA) aqueous solution (concentration: 5%) to the powder obtained in the fourth step, and using a drying tower or a granulator to form spherical and fluid powder particles. .

Step 6. Using a press (manual or automatic packing) to form the powder particles into a compact of the desired shape, using double-sided pressing, the pressing pressure is 100 MPa; or, using a single injection molding technique, the desired shape can also be obtained. Compacted blank.

Step 7. Place the green compact into a sealed high temperature resistant alumina crucible for continuous sintering. Among them, the highest sintering temperature is 1400 ° C, and the holding time is 6 hours.

Step 8. Take out the fired ceramic blank and obtain the desired test sample size by surface treatment such as grinding and polishing. Then, the dielectric performance indicators measured by network analyzer are: sr=38.6; Xf=-25.8ppm/°C; Q χ f=78000 (test frequency is 10GHz) „

Embodiment 5

Since the third embodiment has a good dielectric constant and a good quality factor, and the temperature drift is small, in the present embodiment, the same process parameters as those in the third embodiment are used to perform trial production and detection of different group distribution ratio samples, thereby The above examples are applied to specific environments for detailed description. The basic performance indexes of the obtained samples are shown in Table 1.

Table 1 Dielectric properties of different components (X) ratio (lx) SrTi0 ₃ -xLaA10 ₃ sample

Embodiment 6

Taking the third embodiment (0.52SrTiO ₃ -0.48LaAlO ₃ ) powder as the basic ratio, an appropriate amount of modified dopant, modifying additive and sintering aid are added, and the modified dopant is a rare earth element-containing oxide, rare earth The elements are one or more of lanthanum, cerium, lanthanum, cerium, lanthanum, cerium, 4L, lanthanum, cerium and lanthanum. The modifying additives are CaO, SrO, Ti0 ₂ , ZnO, A1 ₂ 0 ₃ , Nb ₂ 0 _And one or more of Ta ₂ 0 ₅ , the sintering aid is one or more of Bi ₂ 0 ₃ , B ₂ 0 ₃ , CuO, V ₂ 0 ₅ and BaO, the microwave dielectric ceramic material formula According to the chemical formula (lx^rTiOs—x^ai-yReyAlC^], the molar percentages x and y therein satisfy 0.3 mol% < x < 0.9 mol%, 0.1 mol% < y < 0.5 mol%, respectively, wherein the modified additive The mass percentage is 1% to 4% of the total amount of barium carbonate, aluminum oxide, barium oxide and titanium dioxide, and the mass percentage of the sintering aid is 0.1% to 1% of the total amount of barium carbonate, aluminum oxide, barium oxide and titanium dioxide, and is used. Sample trial and test of the same process parameters, so that the above embodiments of the present invention are applied to specific environments for detailed description, The basic performance indicators are shown in Table 2-4. Table 2 Dielectric properties of doped samples modified with different ratios of rare earth elements

Table 3 Dielectric properties of samples corresponding to different proportioning modified additives

Table 4 Dielectric properties of samples corresponding to different proportions of sintering aids

The embodiment of the invention provides a combination of high-energy ball milling technology on the basis of the traditional mechanical mixing and solid phase reaction method, and the ceramic powder is uniformly refined by the first high-energy ball milling, which not only effectively reduces the powder pre-preparation. The temperature is burned, and the ceramic powder having a high purity of the main crystal phase is ensured. The second high-energy ball milling promotes further uniform refinement of the powder particles, lowers the sintering temperature, and ensures high densification of the ceramic body.

Referring to Fig. 2, there is shown a particle size distribution diagram of a powder prepared by conventional mechanical mixing (a) and first high energy ball milling (b) in a method for preparing a microwave dielectric ceramic material according to an embodiment of the present invention.

It can be clearly seen from the figure that when the carbonate is barium carbonate, the particle size of the powder prepared by the preparation method of the microwave dielectric ceramic material of the invention is highly concentrated and the particle size distribution range is narrow, generally less than 1 μ ηι, And has a quality factor of 0.

Referring to FIG. 3, FIG. 3 illustrates a method for preparing a microwave dielectric ceramic material according to an embodiment of the present invention, which uses a conventional mechanical mixing + solid phase reaction method (a) and a mechanical mixing combined with high energy ball milling method of the present invention (b). A scanning electron microscope (SEM) image of a STLA-based microwave dielectric ceramic sample was prepared.

It can be clearly seen from the figure that when the carbonate is barium carbonate, the microwave dielectric ceramic material prepared by the preparation method of the microwave dielectric ceramic material of the invention has no obvious cracks and local pores, and the ceramic particles are uniformly distributed and highly dense. .

Example 7

A method for preparing a microwave dielectric ceramic material, wherein the carbonate is a carbonic acid, the preparation method comprises:

Step 1. Pre-sintering the cerium oxide raw powder at 800 ° C for 2 hours before the batching, and pre-sintering the titanium dioxide raw powder at 1280 ° C for 3 hours to dry; according to the chemical formula 0.88Ca ₁₊ . _.15m . _1% TiO ₃ —0.12LaAlO ₃ The calcium carbonate, aluminum oxide, cerium oxide and titanium dioxide mixed powder are placed in a spherical tank for mechanical homogenization; zirconia grinding balls are added as grinding media, and anhydrous ethanol or deionized is added. Water is used as an organic solvent, and after the powder particles are formed, the organic solvent is removed and dried, and the ratio of the mixed powder, the grinding ball, and the solvent (weight) is 1:3:3 and accounts for 80% of the volume of the spherical tank. The time is 1 hour.

In the present embodiment, the stoichiometric ratio of calcium carbonate and titanium oxide was 0.88 mol%, and the stoichiometric ratio of alumina and cerium oxide was 0.12 mol%. It should be noted that the purity of the carbonic acid 4 and alumina powders is greater than 99.5%, and the purity of the titanium dioxide and cerium oxide powders is not less than 99.9%. Step 2: using the zirconia grinding ball as a grinding medium, drying the powder of the first step, and performing the first high-energy ball milling to obtain a uniformly refined mixed raw material. Among them, the high-energy ball milling time is 1 hour, the ball-to-batch ratio is 10:1, and the rotation speed is 800 rpm.

Step 3: The mixed raw material of the second step is placed in a sealed high temperature resistant crucible, and a precursor powder having a high purity main crystalline phase is synthesized by a high temperature calcination reaction; the calcination temperature is 1200 degrees Celsius, and the holding time is 3 hours.

Step 4: using a zirconia grinding ball as a grinding medium, and subjecting the calcined powder to a second high-energy ball milling to obtain a ceramic powder which is further uniformly refined. Among them, the high-energy ball milling time is 1 hour, the ball-to-batch ratio is 10:1, and the rotation speed is 1000 rpm.

Step 7. Place the green compact into a sealed high temperature resistant alumina crucible for continuous sintering. Among them, the maximum sintering temperature is 1500 ° C and the holding time is 4 hours.

Step 8. Take out the fired ceramic blank and obtain the desired test sample size by surface treatment such as grinding and polishing. Then, the dielectric performance indicators measured by the network analyzer are: £ _r =45..4;

Ti = 7.2 ppm / ° C; Q χ f = 47800 (test frequency is 1.1 GHz).

Example eight

Step 1. Pre-sintering the cerium oxide raw powder at 800 ° C for 2 hours before compounding, and pre-sintering the titanium dioxide raw powder at 1280 ° C for 3 hours to dry; according to the chemical formula 0.52Ca ₁₊ . . _2m . _1% TiO ₃ —0.48LaAlO ₃ The calcium carbonate, aluminum oxide, cerium oxide and titanium dioxide mixed powder are placed in a spherical tank for mechanical homogenization; the zirconia grinding ball is added as a grinding medium, and anhydrous ethanol or deionized is added. Water For the organic solvent, the ratio of the mixed powder, the grinding ball, and the solvent (weight) was 1:3:3 and it accounted for 60% of the volume of the spherical tank, and the mixing time of the raw materials was 2 hours.

In the present embodiment, the stoichiometric ratio of calcium carbonate and titanium oxide was 0.72 mol%, and the stoichiometric ratio of alumina to cerium oxide was 0.28 mol%. It should be noted that the purity of the carbonated carbon and alumina powders is more than 99.5%, and the purity of the titanium dioxide and cerium oxide powders is not less than 99.9%.

Step 2: using the zirconia grinding ball as a grinding medium, the first dry powder is subjected to the first high-energy ball milling to obtain a uniformly refined mixed raw material. Among them, the high-energy ball milling time is 1 hour, the ball-to-batch ratio is 12:1, and the rotation speed is 1000 rpm.

Step 4: using a zirconia grinding ball as a grinding medium, and subjecting the calcined powder to a second high-energy ball milling to obtain a ceramic powder which is further uniformly refined. Among them, the high-energy ball milling time is 1 hour, the ball-to-batch ratio is 10:1, and the rotation speed is 800 rpm.

Step 8. Take out the fired ceramic blank and obtain the desired test sample size by surface treatment such as grinding and polishing. Then, the dielectric performance indicators measured by the network analyzer are: s _r = 34.6;

; Q χ f=41300 (test frequency is 1.1GHz).

Example nine

A method for preparing a microwave dielectric ceramic material, wherein the carbonate is carbonic acid 4 bow, the preparation method Includes:

Step 1. Pre-sintering the cerium oxide raw powder at 800 ° C for 2 hours before batching, and pre-sintering the titanium dioxide raw powder at 1280 ° C for 3 hours to dry; according to the chemical formula 0.36Ca _{1+ 35 m} . _1% TiO ₃ — 0.64LaAlO ₃ The calcium carbonate, aluminum oxide, cerium oxide and titanium dioxide mixed powders are placed in a spherical tank for mechanical mixing; the zirconia grinding balls are added as grinding media, and anhydrous ethanol or deionized is added. Water is used as an organic solvent, and the ratio of the mixed powder, the grinding ball, and the solvent (weight) is 1:3:3 and it accounts for 70% of the volume of the spherical tank, and the mixing time of the raw material is 8 hours.

In the present embodiment, the stoichiometric ratio of calcium carbonate and titanium oxide was 0.36 mol%, and the stoichiometric ratio of alumina to cerium oxide was 0.64 mol%. It should be noted that the purity of the carbonated carbon and alumina powders is more than 99.5%, and the purity of the titanium dioxide and cerium oxide powders is not less than 99.9%.

Step 2: using the zirconia grinding ball as a grinding medium, the first dry powder is subjected to the first high-energy ball milling to obtain a uniformly refined mixed raw material. Among them, the high-energy ball milling time is 2 hours, the ball-to-batch ratio is 10:1, and the rotation speed is 600 rpm.

Step 4: using a zirconia grinding ball as a grinding medium, and subjecting the calcined powder to a second high-energy ball milling to obtain a ceramic powder which is further uniformly refined. Among them, the high-energy ball milling time is 2 hours, the ball-to-batch ratio is 8:1, and the rotation speed is 1000 rpm.

Step 7. Place the green compact into a sealed high temperature resistant alumina crucible for continuous sintering. Among them, the highest sintering temperature is 1400 ° C, and the holding time is 6 hours. Step 8. Take out the fired ceramic blank and obtain the desired test sample size by surface treatment such as grinding and polishing. Then, the dielectric performance indicators measured by the network analyzer are: £ _r = 35.6;

Ti = -12.9 ppm / ° C; Q χ f = 40000 (test frequency is 1.1 GHz).

Example ten

The trial production and detection of different group distribution ratio samples are carried out by using the same process parameters as the preparation method of the microwave dielectric ceramic material of the eighth embodiment, so that the above embodiments of the present invention are applied to specific environments for detailed description, and the basic performance indexes of the obtained samples are detailed. See Table 1.

Table 1 Dielectric properties of different compositions (X) ratio (lx) Ca (l + 0.2 mol%) TiO ₃ -xLaAlO ₃ sample

Embodiment 11

According to the process parameters of the preparation process of the seventh embodiment, a modified dopant, a modification additive and a sintering aid are added in an appropriate amount, and the modified dopant is an oxide containing a rare earth element, and the rare earth elements are lanthanum, cerium, lanthanum, cerium, One or more of cerium, lanthanum, 4L, lanthanum, cerium, and lanthanum, and the modifying additive is one of CaO, SrO, Ti0 ₂ , ZnO, A1 ₂ 0 ₃ , Nb ₂ 0 _{5 ,} and Ta ₂ 0 ₅ Or several, the sintering aid is one or more of Bi ₂ 0 ₃ , B ₂ 0 ₃ , CuO, V ₂ 0 ₅ and BaO,

The composition of the microwave dielectric ceramic material according to the chemical formula of 0.88Ca ₁₊ yTiO ₃ —0.12 [La _1-z Re _z A10 ₃ ] wherein the molar percentages y and z respectively satisfy 0. lmol% < y < 0.5 mol% and 0.01 mol % < z < 0.1mol%, wherein the mass percentage of the modified additive is 1% to 4% of the total amount of carbonic acid 4, alumina, cerium oxide and titanium dioxide, and the mass percentage of the sintering aid is carbonic acid 4 bow, alumina , the total amount of cerium oxide and titanium dioxide is 0.1%~1%, and the same process parameters are used for sample trial production and testing, so that the above embodiments of the present invention are applied to specific environments for detailed description. The basic performance indexes are shown in Table 2-5. . Table 2 Dielectric properties of different molar fractions of carbon tetrachloride corresponding samples

Table 3 Dielectric properties of doped samples modified with different ratios of rare earth elements

Table 4 Dielectric properties of samples corresponding to different proportioning modified additives

Table 5 Dielectric properties of samples corresponding to different proportions of sintering aids

The embodiment of the invention provides a combination of high-energy ball milling technology on the basis of the traditional mechanical mixing and solid phase reaction method, and promotes the uniform refinement of the ceramic powder by the first high-energy ball milling, which not only effectively reduces the pre-firing temperature of the powder, but also ensures the reaction. A ceramic powder of a high purity main crystalline phase is synthesized. Through the second high-energy ball milling, the powder particles are further densified, the sintering temperature is lowered, the high density of the fired ceramic body is ensured, and the molar percentage of the volatile element Ca is increased in the raw material, thereby suppressing the sintering process. The "defective effect" caused by the volatile element Ca.

Referring to FIG. 4, FIG. 4 shows a method for preparing a microwave dielectric ceramic material according to an embodiment of the present invention, which is subjected to conventional mechanical mixing (12 hours) (a) and first high energy ball milling (2 hours) (b). The particle size distribution map of the powder was separately prepared.

In the figure, the abscissa is the particle size diameter in μm, the left ordinate is the percentage of the powder, the unit is %, and the right ordinate is the quality factor Q, the unit is on%. It can be clearly seen from the figure that when the carbonate is calcium carbonate, the particle size obtained by the preparation method of the microwave dielectric ceramic material of the invention is highly concentrated, the particle size is narrowed, and the diameter is generally smaller than Ι μ ηι, and Has a high quality factor Q.

Referring to FIG. 5, FIG. 5 illustrates a method for preparing a microwave dielectric ceramic material according to an embodiment of the present invention, which uses a conventional mechanical mixing + solid phase reaction method (a) and a mechanical mixing combined with high energy ball milling method of the present invention (b). Scanning electron microscopy (SEM) images of CTLA-based microwave dielectric ceramic samples were prepared.

It can be clearly seen from the figure that when the carbonate is 4丐 carbonate, the microwave dielectric ceramic material prepared by the preparation method of the microwave dielectric ceramic material of the invention has no obvious cracks and local pores (pores), and the ceramic particles thereof. The distribution is hooked and highly dense.

In the above manner, the preparation method of the microwave dielectric ceramic material of the present invention is in the process of being produced Two high-energy ball milling can greatly reduce the sintering temperature and shorten the sintering time, and achieve high densification, thereby reducing the production cost and technical difficulty. The obtained microwave dielectric ceramic material has an intermediate electrical constant and a high quality factor. Further, when the carbonate is 4 cerium carbonate, an appropriate amount of the molar percentage of the volatile element Ca in the raw material is used to suppress the "defective effect" of the Ca element being easily volatilized.

The above is only the embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the specification and the drawings of the present invention may be directly or indirectly applied to other related technologies. The scope of the invention is included in the scope of patent protection of the present invention.

Claims

A method for preparing a microwave dielectric ceramic material, comprising:

The mixed powder of carbonate, alumina, cerium oxide and titanium dioxide is mechanically mixed to form powder particles, wherein the carbonate is calcium carbonate or barium carbonate;

Performing a first high-energy ball milling on the powder particles to knead the powder particles; and calcining the first high-energy ball-milled powder in a sealed container at a high temperature to form a precursor powder; The precursor powder is subjected to a second high-energy ball milling to further uniformly refine the precursor powder to form a ceramic powder.

The method for preparing a microwave dielectric ceramic material according to claim 1, wherein the second high energy ball milling step further comprises:

Spray granulation, a polyvinyl alcohol aqueous solution having a concentration of 5% and a mass percentage of 5% to 10% is added to the ceramic powder, and the ceramic powder is made into powder particles having spherical fluidity.

The method of preparing a microwave dielectric ceramic material according to claim 2, wherein the step of the spray granulation further comprises:

Press molding, the spherical fluid powder particles are formed into a compact of a desired shape.

The method for preparing a microwave dielectric ceramic material according to claim 3, wherein the press molding step further comprises:

Sintering, the compact is continuously sintered to form a ceramic blank, wherein the highest sintering temperature is 1300 to 1500 degrees Celsius, and the holding time is 3 to 6 hours.

The method for preparing a microwave dielectric ceramic material according to claim 1, wherein, in the high-temperature calcination step, the sealed container is resistant to high temperature, the calcination temperature is 1100 to 1350 degrees Celsius, and the holding time is 3 to 5 hours.

The method for preparing a microwave dielectric ceramic material according to claim 1, wherein the precursor powder is subjected to a second high-energy ball milling step, and a modified dopant, a modifying additive, and a sintering aid are further added. .

7. The method of preparing a microwave dielectric ceramic material according to claim 6, wherein the modification The dopant is an oxide containing a rare earth element, and the rare earth element is one or more of lanthanum, cerium, lanthanum, cerium, lanthanum, cerium, lanthanum, cerium, lanthanum and town, and the modified additive is CaO. One or more of SrO, Ti0 ₂ , ZnO, A1 ₂ 0 ₃ , Nb ₂ 0 ₅ and Ta ₂ 0 ₅ , the sintering aids are Bi ₂ 0 ₃ , B ₂ 0 ₃ , CuO, V ₂ 0 ₅ and one or more of BaO.

The method of producing a microwave dielectric ceramic material according to claim 7, wherein the carbonate is a carbonate chain.

The method for preparing a microwave dielectric ceramic material according to claim 8, wherein a molar percentage of the alumina and cerium oxide in the powder is 0.15 mol% to 0.45 mol%, and the cerium carbonate and titanium oxide The molar percentage is from 0.1 mol% to 0.7 mol%, the purity of the cerium carbonate and the aluminum oxide are both greater than 99.5%, and the purity of the titanium dioxide and cerium oxide is not less than 99.9%.

The method for preparing a microwave dielectric ceramic material according to claim 8, wherein the step of mechanically mixing the mixed powder of lanthanum carbonate, aluminum oxide, cerium oxide and titanium dioxide comprises: adding oxidizing to the spherical tank The zirconium grinding ball is used as a grinding medium, and the mixed powder is mechanically mixed by adding anhydrous ethanol or deionized water as an organic solvent, and after the powder particles are formed, the organic solvent is removed and dried, wherein the powder is mixed and ground. The weight ratio of the medium and the organic solvent is 1:3:3 and accounts for 60%~80% of the volume of the spherical tank, and the mixing time is 6-10 hours.

The method for preparing a microwave dielectric ceramic material according to claim 8, wherein the powder particles are subjected to a first high energy ball milling step, the ball to material ratio is 8:1 to 10:1, and the ball milling time is 3. ~6 hours, the speed is 400~800 rev / min.

The method for preparing a microwave dielectric ceramic material according to claim 8, wherein the precursor powder is subjected to a second high energy ball milling step, the ball to material ratio is 10:1 to 12:1, and the ball milling time is 3 ~6 hours, the speed is 600~1000 rev / min.

The method for preparing a microwave dielectric ceramic material according to claim 12, wherein the ceramic powder after the second high energy ball milling has a particle size of less than 1 μηη.

The method for preparing a microwave dielectric ceramic material according to claim 8, wherein the formula of the microwave dielectric ceramic material is a molar percentage thereof according to a chemical formula (lx) SrTi0 ₃ —x[La^ReyA10 ₃ ] x and y respectively satisfy 0.3 mol% < x < 0.9 mol%, 0.1 mol% < y < 0.5 mol%, wherein the mass percentage of the modifying additive is 1 of total amount of cerium carbonate, aluminum oxide, cerium oxide and titanium oxide. %~4%, the mass percentage of the sintering aid is 0.1% to 1% of the total amount of lanthanum carbonate, aluminum oxide, cerium oxide and titanium dioxide.

The method of producing a microwave dielectric ceramic material according to claim 7, wherein the carbonate is calcium carbonate.

The method for preparing a microwave dielectric ceramic material according to claim 15, wherein the formula of the microwave dielectric ceramic material is a molar percentage thereof according to a chemical formula (lx) Ca ₁₊ yTi0 ₃ —x[La^Re _z A10 ₃ ] x, y, and z satisfy 0.1 mol% < x < 0.7 mol%, 0.1 mol% < y < 0.5 mol%, and 0.01 mol% < z < 0.1 mol%, respectively, and the purity of the calcium carbonate and alumina are both greater than 99.5%. The titanium dioxide and cerium oxide have a purity of not less than 99.9%.

The method for preparing a microwave dielectric ceramic material according to claim 15, wherein the step of mechanically mixing the mixed powder of calcium carbonate, aluminum oxide, cerium oxide and titanium dioxide comprises: adding oxidizing to the spherical tank The zirconium grinding ball is used as a grinding medium, and the mixed powder is mechanically mixed by adding anhydrous ethanol or deionized water as an organic solvent, and after the powder particles are formed, the organic solvent is removed and dried, wherein the powder is mixed and ground. The weight ratio of the medium and the organic solvent is 1:3:3 and accounts for 60%~80% of the volume of the spherical tank, and the mixing time is 1-3 hours.

The method for preparing a microwave dielectric ceramic material according to claim 15, wherein the powder particles are subjected to the first high energy ball milling step, the ball to material ratio is 8:1 to 10:1, and the ball milling time is 1 ~3 hours, the speed is 600~800 rev / min.

The method for preparing a microwave dielectric ceramic material according to claim 15, wherein the precursor powder is subjected to a second high-energy ball milling step, the ball-to-batch ratio is 10:1 to 12:1, and the milling time is 1 ~3 hours, speed 800~1000 rev / min.

The method for preparing a microwave dielectric ceramic material according to claim 15, wherein the formulation of the microwave dielectric ceramic material is based on a chemical formula (lx) Ca ₁₊ yTi0 ₃ —x[La _1-z Re _z A10 ₃ ] The molar percentages x, y, and z satisfy 0.1 mol% < x < 0.7 mol%, 0.1 mol% < y < 0.5 mol%, and 0.01 mol%, respectively. <z<0.1 mol%, wherein the mass percentage of the modifying additive is 1% to 4% of the total amount of carbonic acid 4, alumina, cerium oxide and titanium dioxide, and the mass percentage of the sintering aid is carbonic acid 4 bow , a total of 0.1% of alumina, yttria and titania.